A number of studies have reported that Vitamin E administered orally may reduce the severity of retrolental fibroplasia (RLF) in preterm infants. However, results from these studies are variable and conflicting. Additionally, orally administered Vitamin E in preterm infants has been associated with systemic toxicity including a higher incidence of necrotizing enterocolitis. It is proposed that the major problem in Vitamin E therapy for RLF in preterm infants involves the lack of selective distribution of Vitamin E to the target tissues (retina). Therefore, topical application of Vitamin E may be useful in the treatment of RLF in preterm infants and may eliminate the problems associated with oral administration. This study will examine the endogenous levels of tocopherol in retinal as well as other vital tissue (e.g., lung, liver, brain) and evaluate the disposition and therapeutic efficacy of topically applied tocopherol compared with parenterally administered Vitamin E in prevention of oxygen-induced RLF. The kitten has been chosen as the experimental model for these studies. This model has proven to be much like the human disease with considerable variation between the left and right eyes, as well as between animals from a different genetic background. In the selection of this animal model it is recognized that unlike the human the kitten fails to develop retinal detachment after severe oxygen stress. These studies will be done in two phases. During the first phase, distribution of both parenteral and topically administered Vitamin E in the newborn kitten will be studied using radiolabeled 3H d-1 tocopherol. The use of 3H tocopherol will enable differentiation of exogenously administered Vitamin E from endogenous levels. In the second phase, the efficacy of the Vitamin E administered parenterally or topically in decreasing the severity of oxygen-induced RFL in the newborn kitten will be assessed.